In radiotelephone systems, handoff is required to maintain communication to a subscriber as it moves from one cellular coverage area to another. During handoff, a base-station communicating to a subscriber in a source cell, transfers communication from the source base-station to a target base-station in a cell in which the subscriber may also communicate. Typical radiotelephone systems employ scanning receivers in the base-stations, which, when in a target base-station, continuously scan the transmission of the subscriber. The use of scanning receivers, however, increases handoff message load throughout the system due to handoff initiation messages, handoff measurement requests, and handoff acknowledgments required.
Digital radiotelephone systems incorporate methods to help mitigate the message overload problem of typical radiotelephone systems. One such method has been to allow the subscriber or mobile to assist in the handoff process. This feature of mobile assisted handoff (MAHO) used in digital radiotelephone systems helps alleviate the requirement of scanning receivers by allowing the mobile to perform a similar such measurement on candidate target base-stations transmissions. In some radiotelephone systems, however, the mobile does not identify the source of the signal, so it is possible that the source of a measured signal is an interferer. Without knowledge of where the measured signal is actually originating from, using MAHO to determine the best target sector or target cell in a radiotelephone system would seem risky at best.
Thus, a need exists for a radiotelephone system which provides positive verification that a target sector or target cell picked by MAHO is a truly viable target.